Water-cooled lead chamber



April 4, 1944- A. M. FAIRLIE WATER-COOLED LEAD CHAMBERS File d Aug. 50, 1940 2 Sheets-Sheet 1 INVENTQR April 1 A. M. FAIRLIE 2,345,661

WATER-COOLED LEAD CHAMBERS Filed Aug. 30. 1940 2 Sheets-Sheet 2 Patented Apr. 4, 1944 UNITED STATES PATENT OFFICE 11 Claims.

This invention relates to lead chambers, such as are commonly used for the manufacture of sulfuric acid, that are capable of being watercooled externally, and to means for materially extending the surfaces thereof to which cooling water may be convenietly and effectively ap plied.

While the devices herein described may be applied to any lead chamber that is capable of being externally cooled with flowing water, they are more especially adapted for use with chambers whose walls slope outwardly from top to bottom, whether the cross-sectional shape of such chamber be circular, oval, square, rectangular or any other shape. An example of a chamber whose walls slope outwardly from top to bottom is the water-cooled chamber of frustopyramidal or frusto-conical shape (a cone being a limiting case of the generic term pyramid), known as the Mills-Packard sulfuric acid chamber, described in U. S. Patent No. 1,112,546, later modified as described in U. S. Patent No. 1,627,043.

It is common practice to construct sulfuric acid chambers of sheet lead, the lead sheets being burned (welded) together (in that form being commonly termed curtains in the art) and supported from a frame-work of wood or steel.

The pan of the chamber is the dish or saucer at the bottom of the chamber in which the condensed acid is collected. The chamber pan, likewise made of sheet lead, comprises a bottom or floor and upstands or side walls-the latter usually two or three feet highand the bottom:

and upstands usually are made of thicker lead sheets than the rest of the chamber. There are two types of chamber pan-the luted pan, in which the lower part of the chamber curtains (side-walls) extends inside the pan upstand and dips into the acid contained in the pan to form a liquid seal which prevents the escape of chamber gas or the entrance of air into the chamber; and the burned pan, in which the lowest two or three feet of the chamber curtains, rolled at the lead mill to a greater thickness than the rest of the sheet, constitutes the pan upstand, and is burned (welded) directly to the lead bottom of the chamber. With either the luted or the burned pan, it is customary to brace the upstand against the outward thrust of the acid contained in the pan by means of boards laid against the outside of the upstand and held in place by suitable bracing of wood or steel.

In the case of a water-cooled chamber having the luted type of pan, it has been the practice heretofore, in order to prevent the cooling water flowing down the chamber sides from entering the chamber pan and thus diluting the acid therein, to place a trough or gutter for collecting the cooling Water above the top of the pan upstand. Prior to this invention, the same procedure was followed in the case of water-cooled chambers having the burned type of pan, the conventional form of burned. pan, with upstands supported outside by boards or the like, being unsuitable (partly because of such supporting elements) for external cooling of the lead of the pan upstand, either by air or by water. My present invention involves the elimination of the wooden supports for the pan upstand, and the provision of a chamber pan Whose upstand is at once stoutly braced against outward thrust and adapted to cooling by means of water flowing over, its external surfaces. The invention is applicable more readily to the burned type of chamber pan; but it can be applied also to the luted type of pan, as explained below.

One object of this invention is to increase substantially the water-cooled area of a watercooled lead chamber by providing means Whereby the cooling water may flow, not only over the chambertop and over the curtains above the top of the pan upstand, but also over the outside of the pan upstand itself, into a trough surrounding the bottom of the pan upstand.

Another object is, by water-cooling the angle of the chamber pan, where the lower part of the upstand is bent or flanged from an upright to a horizontal position on the chamber floor (heretofore the most rapidly corroded part of a lead chamber), to materially reduce the temperature of the lead at said angle as well as to reduce the temperature of the acid contained in the chamber pan, and thus to prolong the life of the chamber pan and reduce the maintenance cost of the latter.

Other objects are, by means of devices describe-:1 herein, to eliminate the wooden pan-upstand support that acted, in the prior practice, to keep the lead pan and its acid contents heated and thus to shorten the life of the chamber pan, and at the same time to provide a type of upstand and support therefor, adapted to the effective application of cooling water.

- The invention is illustrated in the annexed drawings in which Figure 1 is a sectional elevation of the lower part of one side of a conical water-cooled lead chamber embodying examples of the improvements herein described, and Fi ure 2 is a sectional plan on the line A-A of Figure 1. Figure 3 is a showing of the application of the present invention to a luted pan chamber, of the above type. Figure 4 is an elevation of a chamber, a part of this being shown in section, with one of the substantially vertical steel beams, and one set of the chamber wall (curtain) supports illustrated, and showing several of the rigid supporting ribs, for preventing bulge of the pan upstand. In all figures, like numbers indicate like parts.

In the drawings, l represents a conical-shaped lead chamber designed to :be cooled externally. by means of water applied at the chamber top and allowed to flow downwardly over'the leadcurtains. 'The latter, usually of v.lead weighing six or seven pounds per square foot (called 6 or '7-lb. lead), is indicated by 2, and the'pan upstand (usually of 10-, 12- or 15-lb. lead), by 3. The symbol 4 indicates-the top of the pan upstand, or (in the case of the burned pan) the junction of pan upstand with lead curtain. The top of the platform floor on which the chamber rests is indicated by 5, the lead bottom (preferably of the same lead thickness as the upstand) by 6, the flanged portion of the pan upstand by l, and the lead seam joining the pan bottom to the upstand by 8. For the external support of the upstand 3, ribs 9,'made of pure lead, antimonial lead, or other acid-resistant metal, are secured to or against the lead upstand on the outside of the chamber pan. These ribs may be of any suitable size, but a convenient size is 1% inches wide by of an inch thick and approximately as long as the upstand is high. These ribs are preferably curved on their outer edges at top and bottom to avoid sharp corners, and the thickness of ach rib is usually beveled at the top, to avoid spattering the cooling water. The ribs, if of lead, are preferably burned to the lead upstands in spots (tacked), as continuous burning is unnecessary. Downward extensions of the curtain fins or lugs described in U. S. Patent No. 1,627,043 maybe used as upstanding supporting ribs, if desired. On reference to said patent it will be observed that the lead curtains of the chamber are supported by steel angles secured to a series of upstanding steel T-bars surrounding the chamber, the connection between lead curtain and said steel angle being (1) a series of upstanding lead fins or lugs substantially parallel to the slope of the chamber wall and burned (welded) thereto, each lug being stiffened by a fiat steel bar on each side; (2) a series of bolts passing through both flat steel bars and the lead lugs between them; (3) a series of pivoted steel links bolted at one end to the flat steel bars and .the lead lug between them and at the other end to the eye of an eye-bolt passing through a bolthole in said steel angle and also through a thick rubber washer, said eye-bolt being secured in place by an adjustable nut engaging with the upper (threaded) end of said eye-bolt. As an'additional means (in the apparatus of my present application) of bracing the pan upstand, the entire complement of ribs (spaced usually two'or three feet apart) around any chamber maybe encircled by one or more metallic bands vH1, resting in notches ll provided in the ribs, and the tension of these bands may be adjustable by known means, e. g.,'by turn buckles Illa. One

purpose of the ribs is to keep the bands at a distance of at least of an inch from the surface of the pan upstand and thus out of the flowing water. If the tension of the bands is adequate to hold them in position without notches in the ribs, the notches maybe omitted. If the tension of the bands is sufiicient to hold the ribs in position without burning to the upstand, the latter operation may be omitted. For the bands, circles of rod, pipe, or other form of tie may be substituted. The trough 52 for collecting the cooling water flowing down the chamber sides may be placed at any convenient place below the top of the pan upstand, but the preferred location for it is on the chamber-platform floor 5, between the pan upstand and the base angle ring is of the chamber framing, and close enough to the pan upstand to be burned directly to it. This trough can usually be of 6-lb. sheet lead, and its inner side it may be burned at M to the pan upstand, while its outer side 15 may be turned over the top edge of the base angle ring Iii. The gusset plate I? is used for bolting the T-bar 18 to the base angle ring 16. l

The foregoing description applies to the burned type of pan. To apply this invention to the luted type of pan, the water collecting trough and the supports for the pan upstand may be constructed as above described, and an apron 2A of 6- or 7-lb. sheet lead may be burned at its upper edge to the curtain around its perimeter, a little, above the top of the pan upstand, while the lower edge of said apron is dressed into place immediately outside of the top of the pan upstand, in such a way as to shed the down-flowing cooling water from the curtains on to the outside surfaoeof the pan upstand, avoiding the possibility of in troducing cooling water into the acid contained in the pan, and effecting the cooling by water of the pan and the angle thereof as above described. In practice, with either type of pan, the cooling water flowing down the chamber sides, -instead of as heretofore being caught in a trough located above the pan upstand (thus leaving the lower part of the chamber without any "water on its outside), continues toflow downward to the very bottom of the chamber, and is collected in a trough located at the chamber 'fioor and annexed to (i. e., surrounding and in contact with) the chamber .pan at ornear its bottom. By this means from 5 to '7 per cent or more of additional chamber surface derives the benefit of water cooling, the most vulnerable part of the chamber, namely, the angle at the bottom of the pan upstand is also water-cooled, and the acid contained in the pan is water-cooled, thus materially reducing the temperatures of the lead of the chamber pan and of the acid contained therein, with substantial reduction in the lead depreciation rate and in maintenance expense. These benefits are attained by eliminating .the old methods of pan-upstand support, which prevented the water'cooling of the pan upstand, and by locating the cooling-water collecting trough lower down on the chamber than was usually practiced in the prior art, and preferably on the chamber-platform floor.

The present invention, in its preferred form, thus accomplishes two important advantages, (a) it allows supporting the pan upstand against the lateral thrust of the sulphuric acid in the pan, and (b) it allows cooling the pan upstand, even down to its bottom (the joint or angle of the pan upstand with the pan bottom, a place where corrosion is ordinarily considerable). And in the preferred form of the invention, neither of these interferes with the other.

While this invention has been described above in an illustrative manner, obviously modifications deviating from the particular specifications or dimensions mentioned herein could be employed, without departing from the spirit of the invention itself, the scope of which is limited broadly only by the claims hereto appended.

In Figure 4 I have illustrated a well known support for the weight of the lead Walls (commonly called curtains) of the chamber. This is in accordance with the Maudsley Patent 1,627,- 043. In Figure 4 I have shown, attached to the substantially vertical T-bars ill, a series of angle iron rings 24 which encircle the chamber but are spaced therefrom a short distance. At convenient places, vertical fins of sheet lead 22, are burned to the curtain, preferably along a vertical line. As is common, these may extend from near the chamber top to somewhat above the top of the pan upstand. Placed in front of and back of each of these fins 22, are two iron plates or strips 26, to give support. These iron plates 26 are spaced a short distance from the chamber wall 2. Depending from the angle iron rings 24, are eye-bolts 21 (which may be supported on rubber washers to give some play), which are connected to links 25. Bolts 29 connect the links 25 to the plates 25, and serve to press these plates 26 firmly against both sides of the lead fins 22, for giving support to the latter, and thence to the curtains 2. It will :be understood that any desired number of these eye-bolts 21, rubber washers (or equivalent), links 25 and bolts 29, can be provided, and that the top of the chamber can be supported in a suitable manner, from girders spanning the tops of the T-bars I3, all of which form no part of the present invention.

At 30 is illustrated a commonly used water distributor in the form of a lead gutter, the bottom of which is burned to the lead chamber walls,

just below the roof. This may have a serrated top edge. No claim is made to this.

In Figure 4 I have (for clarity) shown only one of the T-bars I 8, but it is to be understood that a ring of these spaced apart from one another, is provided, preferably all sloping somewhat, to be parallel with the nearest part of the chamber wall.

The drawings of this application are not intended to be made to scale, and for clarity of illustration, the thicknesses of the curtains, pan upstand, pan bottom and collecting gutter are purposely exaggerated in the drawings. Chambers of the kind shown are, in many instances, about 50 feet high. The curtains 2 may be made of 6 lb. or '7 lb. lead, and the pan bottom 5 and the pan upstand 3 may be made of 10 1b., 12 lb. or 15 lb. lead, the troughs 2A and [2 may be made of 6 lb. lead. These figures are given, merely by way of example, and not limitation.

I claim:

1. In an apparatus for the manufacture of sulfuric acid, the combination of a lead chamber having the shape of the frustum of a pyramid, a supporting framework therefor including a base angle ring, a chamber-pan at the bottom of such chamber comprising a lead floor and upstanding lead walls united to said floor, means for applying cooling water to the outside of such chamber including the outside of the upstand ing walls of such chamber-pan, and a trough at the bottom of such chamber-pan, external to and surrounding the same, for collecting such cool- (ill water, a large part of the inner wall of said trough being said upstanding lead wall of said chamber-pan, and the outer wall of said trough being supported :by the base angle ring of said chamber framework.

2. In combination, a sulfuric acid chamber of circular cross section with lead walls sloping outwardly from top to bottom and suspended from a supporting framework, said framework including a base angle ring located outside the bottom of said chamber and spaced therefrom, said chamber including a chamber-pan comprising a lead floor and upstanding lead walls united to said floor and stiffened by a plurality of upstanding ribs of rigid material spaced at intervals around the outside of said chamber-pan walls and contiguous thereto and adapted to prevent distortion of said chamber-pan walls by the outward thrust of acid contained in said pan, means for applying cooling water to the outside of the walls of said chamber and chamber-pan, and a trough surrounding said chamber-pan at the bottom thereof, for collecting said cooling water, a large part of the inner wall of said trough being the upstanding lead wall of said chamberpan, and the outer wall of said trough being supported by the base angle ring of said chamber framework.

3. A sulfuric acid chamber as described in claim 2, in combination with one or more metallic ties surrounding said ribs contiguous to said chamber-pan walls, and adapted to retain said ribs in position by means of tension.

4. In combination, a sulfuric acid chamber of circular cross section with lead walls sloping outwardly from top to bottom and suspended from a supporting framework by means of lead fins burned to said walls, such framework including a base angle ring, and with a chamber-pan comprising a lead floor and upstanding lead walls united to said floor, means for applying cooling water externally to the walls of said chamber and chamber-pan, a trough surrounding the bottom of said chamber-pan, for collecting said cooling water, a substantial portion of the inner wall of said trough being the wall of said chamber-pan, and the outer wall of said trough being supported by the base angle ring of said chamber frame- Work, and substantially vertical metallic bracing ribs spaced at intervals around the perimeter of said chamber-pan walls and external thereto and adapted to prevent distortion of said pan Walls by the outward thrust of acid contained in said chamber-pan.

5. A sulfuric acid chamber as described in claim 4, in combination with one or more metallic ties surrounding said bracing ribs and adapted to retain same rigidly in position by 'means of tension.

6. An apparatus for the manufacture of sulfuric acid by the chamber process, which apparatus comprises a lead chamber having a top and side walls capable of being cooled externally with flowing water, a chamber-pan at the base of such chamber, said pan comprising a lead bottom, upstanding lead walls united to said bottom, a supporting framework capable of supporting the side walls of said chamber, such framework including a base angle ring, a lead trough surrounding the base of said upstanding walls and united to the outside thereof, the outer wall of said trough being supported by the base angle ring of the supporting framework of said chamber, in combination with means for applying cooling water to the outside of the top and side walls of said chamber, said cooling water flowing downwardly to the outside of said upstanding pan walls, and into said trough.

7. In a lead chamber suitable for the manufacture of sulfuric acid, such chamber including a chamber-pan at its bottom, which pan includes a floor and an upstand, a multiplicity of upstanding rigid ribs serving as braces, spaced at intervals around the periphery of the upstand of said chamber-pan, and in contact therewith, and adjustable means pressing said ribs against the upstand of said chamber pan, said ribs and said pressing means being adapted to prevent distortion and bulging of said upstand of said chamber-pan by the weight of acid therein, the total part of the external area of the upstand of the chamber-pan which is covered by said ribs being only a minor fraction of the total external area of said upstand of said chamber-pan, the part of the outside surface of the upstand of said chamber-pan which is between said ribs being a major fraction of the total external area of the upstand of said chamber-pan and" being readily accessible for application thereto of cooling fluids.

8. A lead chamber as in claim 7, in which the chamber-pan is, substantially circular in cross section, and in which the said rigid ribs are pressed against the upstand of the chamber-pan by an adjustable band surrounding said rigid ribs, which band is spaced from said upstand of the chamber-pan.

9. A sulfuric acid chamber as described in claim 2, in which said upstanding ribs are united to said chamber-pan upstand.

10. A sulfuric acid chamber as described in claim 4, in which said upstanding metallic bracing ribs are united to said chamber-pan upstand by a process of leadburning.

11. An apparatus for the manufacture of sulfuric acid as described in claim 7, in which said upstanding rigid ribs are united to the upstand of said chamber-pan by leadburning.

' ANDREW MILLER FAIRLIE-.- 

